I was going to look into ORB myself.
I just recently set up Plex and I think it's fantastic. I haven't dropped the $5 for the phone app just yet, but it looks like it would work for you as well. Plex was very easy to setup and now I can stream my home media all over my house and at work. I'll likely get the app as well - we'll see how good video streams over 3G ...
ORB has been around much longer iirc - would be interested to see a comparison between the two.
* here's a not too exciting clip of someone streaming to their Android phone over 3G
http://www.youtube.com/watch?v=eF0iHq_FYSs